# PY 211 Lecture 10: Chapter 8

Chapter 8

Hypothesis Testing

Inferential Statistics

ļ· Descriptive vs. inferential

o Descriptive ā describes characteristics (CT, Var) of a set of scores (table, graph)

o Inferential ā procedures used for generalizing observations within sample to

population from which it came

ļ· Hypotheses and Testing

o Hypothesis

ļ§ Statements about the value for a population parameter

ļ§ Statements that can be tested using the research method

o Hypothesis testing (significance testing)

ļ§ Method for testing a hypothesis about a population parameter

ļ§ Determine the likelihood that a sample statistic would be selected, given

the population parameter

ļ· Hypothesis

o Null

ļ§ Treatment did not work

ļ§ Sample looks like original distribution (high probability)

o Alternative

ļ§ Treatment worked

ļ§ Sample does not look like original distribution (very low probability)

ļ· Examples

o Water filter

ļ§ Null: sample looks like (polluted) population (high probability)

ļ§ Alternative: sample looks nothing like the population (low probability)

ļ· Much cleaner

ļ· Filter works

o Pain therapy (meditation)

ļ§ Null: saī
µple looks like īhigh paiī
¶ī populatioī
¶ ī¾high proīaīilityīæ

ļ§ Alterī
¶atiīe: saī
µple looks ī
¶othiī
¶g like the īhigh paiī
¶ī populatioī
¶ ī¾loī

probability)

ļ· Feel less pain

ļ· Therapy helps

o Learning, sleeping & memory

ļ§ Null: saī
µple looks just like īī
¶o sleepī populatioī
¶ ī¾high proīaīilityīæ

ļ§ Alterī
¶atiīe: saī
µple looks ī
¶othiī
¶g like the īī
¶o sleepī populatioī
¶ ī¾loī

probability)

ļ· Remember more

ļ· Sleeping helps

Steps in Hypothesis Testing

ļ· Research design

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## Document Summary

Descriptive vs. inferential: descriptive describes characteristics (ct, var) of a set of scores (table, graph) Inferential procedures used for generalizing observations within sample to population from which it came. Statements about the value for a population parameter. Statements that can be tested using the research method: hypothesis testing (significance testing) Method for testing a hypothesis about a population parameter. Determine the likelihood that a sample statistic would be selected, given the population parameter. Sample looks like original distribution (high probability: alternative. Sample does not look like original distribution (very low probability) Null: sample looks like (polluted) population (high probability) Alternative: sample looks nothing like the population (low probability) Null: sa(cid:373)ple looks like (cid:862)high pai(cid:374)(cid:863) populatio(cid:374) (cid:894)high pro(cid:271)a(cid:271)ility(cid:895) Alter(cid:374)ati(cid:448)e: sa(cid:373)ple looks (cid:374)othi(cid:374)g like the (cid:862)high pai(cid:374)(cid:863) populatio(cid:374) (cid:894)lo(cid:449) probability) Therapy helps: learning, sleeping & memory. Null: sa(cid:373)ple looks just like (cid:862)(cid:374)o sleep(cid:863) populatio(cid:374) (cid:894)high pro(cid:271)a(cid:271)ility(cid:895) Alter(cid:374)ati(cid:448)e: sa(cid:373)ple looks (cid:374)othi(cid:374)g like the (cid:862)(cid:374)o sleep(cid:863) populatio(cid:374) (cid:894)lo(cid:449) probability)